Book excerpt: The emergence of social media as one of the driving forces of consumers’ online experiences today also challenges our current understanding on marketing and brand management. The effects of brands’ social media involvement are to this day uncertain. Severin Dennhardt shows that social media and user-generated brands do have a strong influence on brands. Four independent studies demonstrate that first, successful brands can be created in virtual worlds, second, user-generated content drives the creation of unique brands, third social media strongly influences the social value perception of brands, and fourth, social media impacts consumers’ purchase decision process.